The present invention relates to a screening apparatus comprising means for sprinkling liquid into a screen frame having a screen and means for vibrating the screen.
Screening apparatuses of this type, called wet-type screening apparatuses, have been provided to overcome the drawback of inefficient screening operation experienced with apparatuses of the dry type in which the screen is merely vibrated.
The conventional screening apparatus of the wet type includes a screen frame supported in suspension to subject the screen to horizontal oscillations. Such apparatus has the following drawbacks:
1. The swinging motion of the screen causes the water retained in the screen frame to move in horizontal directions therein, with the result that powdery or granular material fails to spread over the screen uniformly, making it impossible to achieve highly efficient and accurate screening operation.
2. Inasmuch as the screen can not sufficiently vibrate relative to the screen frame, with oscillations taking place in horizontal directions, particles or granules trapped in the meshes of the screen are almost unable to rollingly move upward or downward, hence still inefficient operation.
To overcome these drawbacks, this invention provides improvements in the wet-type screening apparatus.